
def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == "__main__":
    main() def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No') main n = int(input()) n int(input()) int input() input if n >= 30:
        print('Yes')
    else:
        print('No') n >= 30 n 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No') def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No') main

def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == "__main__":
    main()
